Children partially paralyzed by myelomeningocele develop progressive hip flexion contractures and increased lumbar lordosis. These deformities interfere with their function to the point that they may stop walking and eventually end up in a wheelchair. The purpose of this project is to develop an orthotic device which will assist hip extension, substituting for the absent muscles on the backside of the hip. It is anticipated that this device will then prevent the progression of hip flexion contracture and lumbar lordosis, improve the child's ability to walk, and decrease the likelihood of corrective surgery.